1. Field of Invention
The present invention relates to a device and method for switching wavelength division multiplexed light signals among optical fibers or other transmission media. 2. Description of Related Art
Optical communication systems are a substantial and rapidly growing party of communication networks. The expression xe2x80x9coptical communication system,xe2x80x9d as used herein, relates to any system that uses optical signals to convey information across an optical transmission device, such as an optical fiber. Such optical systems may include, but are not limited to telecommunication systems, cable television systems, and local area networks (LANs).
While the need to carry greater amounts of data on optical communication systems has increased, the capacity of existing transmission devices is limited. Although capacity may be expanded, e.g., by laying more fiber optic cables, the cost of such expansion is prohibitive. Consequently, there exists a need for a cost-effective way to increase the capacity of existing optical transmission devices.
Wavelength division multiplexing (WDM) has been adopted as a means to increase the capacity of existing optical communication systems. In a WDM system, plural optical signals are carried over a single transmission device, each channel being assigned a particular wavelength.
An essential part of optical communication systems is the ability to switch or route signals from one transmission device to another. Micro-electromechanical mirrors have been considered for switching optical signals. However, this approach is not suitable for use with 10 systems that use wavelength division multiplexed signals because micro-electromechanical mirrors cannot switch between signals of different wavelengths. Another approach utilizes bubbles that are capable of changing their internal reflection. However, this technique is also unable to switch multiple wavelengths individually. Furthermore, both of these devices have limited switching speeds, in the range of 10 kHz for the mirror devices and in the range of 100 Hz for the bubble devices.
Other switching approaches, such as the approach disclosed in U.S. Pat. No. 4,769,820, issued to Holmes, can switch data at GHz rates, which is effectively switching at GHz transition rates. However, this approach requires substantial optical switching power, has potential cross talk, and cannot resolve wavelength over-utilization issues. What is needed is a means for switching wavelength division multiplexed signals that is capable of doing so at high speeds with no cross talk and requires low switching power.
1. Advantages of the Invention
One advantage of the present invention is that it is able to switch signals of different wavelengths.
Another advantage of the present invention is that it is able to switch at high speeds.
Further advantage of the present invention is that it does not require high power.
Another advantage of the present invention is that it does not suffer from crosstalk.
Another advantage of the present invention is that it is able to switch between wavelengths and fibers to avoid transmission device or wavelength over-utilization.
Another advantage of the present invention is that it is able to broadcast to multiple transmission devices or couplers simultaneously.
A further advantage of the present invention is that it is able to regenerate and restore signals.
An additional advantage of the present invention is that it can transmit through air or other intervening media to a receiver without a costly or slow electrical interface.
These and other advantages of the present invention may be realized by reference to the remaining portions of the specification, claims, and abstract.
2. Brief Description of the Invention
The present invention comprises an optical switch device. Tile optical switch device comprises at least one source, a plurality of targets, at least a first and second switch element, and at least one beam splitter. The source is adapted to transmit an optical signal and the plurality of targets is adapted to receive the optical signal. Each switch element comprises a detector, an emitter array, and a switch controller. The detector is positioned to receive light from the source, and it is adapted to detect optical signals. The emitter array is positioned to transmit light to the targets, and the emitter array comprises a plurality of emitters, each emitter being adapted to generate light signals. The switch controller is in communication with the detector and the emitter array. The switch controller is adapted to cause the emitter array to generate the detected signal. The beam splitter is positioned to reflect optical signals to the detector of the first switch element, and the beam splitter is adapted to reflect light within a predetermined range of wavelengths and allow light outside of the predetermined range of wavelengths to pass through the beam splitter. The second switch element is positioned to receive optical signals that pass through the beam splitter and t it optical signals to the plurality of targets.
The above description sets forth, rather broadly, the more important features of the present invention so that the detailed description of the preferred embodiment that follows may be better understood and contributions of the present invention to the art may be better appreciated. There are, of course, additional features of the invention that will be described below and will form the subject matter of claims. In this respect, before explaining at least one preferred embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of the construction and to the arrangement of the components set forth in the following description or as illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting.